Re: Cellular Phones and EPDs

[marni.delong@hydro.on.ca]

To:
     radsafe@romulus.ehs.uiuc.edu
+++++++++
Radsafers,

 I sent this thread to Ross Hirning here at Ontario Hydro and gave him the 
heads up about the particular problems that were being encountered with the 
Siemens EPDs.
He has sent this response in the hopes of providing some clarification to 
all users.
You can reply back to him directly if you require any more information.

Marni DeLong,
Health Physicist, Radiological Services, Ontario Hydro, Canada.
marni.delong@hydro.on.ca
.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-..

Marni,

Here is a summary of the Ontario Hydro experience with EMI and the Siemens 
EPD.  Please pass it on to Radsafe, with my name and e-mail address 
(ross.hirning@hydro.on.ca) as contact for further info.
____________________________________________________________________________

Ontario Hydro and AECL conducted a series of type tests on pre-production 
and early production EPDs in 1993-94.  The results were published in Health 
Physics Vol. 69, pp. 46-66 (1995), and the results of the electromagnetic 
interference (EMI) tests can be summarized as follows (tests were done with 
a simultaneous applied gamma field, except where noted):
 - No interference from pulsed magnetic fields to 800 A/m.
 - No interference from electrostatic fields of 5000 V/m.
 - No interference from electrostatic discharge of 2.25 mJ at 3000 VDC (no 
gamma source).
 - No interference from 60 Hz electric fields at 100 V/m.
 - No interference from 60 Hz magnetic fields at 60 A/m.
 - Possible slight interference from RF fields of 100-500 MHz at 10 V/m.
 - No interference from a 49 MHz field from a 15 W communications 
transmitter, unless antenna in contact with EPD (no gamma source for contact 
test).
 - Limited interference from a 490 MHz field from a 5 W transmitter with 
antenna about 2 cm from face of EPD; strong interference with antenna in 
contact with case (no gamma source for contact test).

More recently, field tests were conducted on a set of Mark 1.2D, 
EMC-enhanced EPDs, as well as on a set of Mark 1.2B, non-EMC enhanced EPDs. 
 A wide variety of sources of electromagnetic radiation found in and around 
nuclear power stations were tried, without any ionizing radiation present 
above normal background.  Interference with the EMC-enhanced EPDs was 
observed with only two sources:
 - the ignition circuit of a propane-powered fork lift truck; and
 - the transmitter for a wireless communications system operating at 2 GHz.
In both cases, the source was within 30 cm of the EPD when interference was 
observed.  Tests with two models of Motorola cellular phone showed no 
interference with the EMC-enhanced EPD, but strong interference was observed 
with the non-enhanced version.

An MGPI electronic dosimeter was also tested with some of the sources, and 
showed interference from a high-frequency welder, a video monitor and the 
fork lift.  It was not tested with the cell phones.

The conclusion is that the EMC-enhanced EPD is resistant to interference 
from most sources of electromagnetic radiation, but there are a few sources 
that will cause interference.  Problems can be avoided by training users on 
how to recognize and avoid EMI, or by putting the dosimeter into a shielded 
bag.


 ----------
From: INTERNET
Subject: gmasters@csn.net: Re: Cellular Phones an
Date: Saturday, October 26, 1996 1:09AM

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Subject: Re: Cellular Phones and EPDs
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Subject:  Re: Cellular Phones and EPDs
Date: 1996-10-26 01:09
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 ----------------------------------------------------------------------------
 
 --

On Thu, 24 Oct 1996, Erick Lindstrom wrote:

> Radsafers:
>
> I just discovered that my Siemens Electronic Personal Dosimeters (EPD-2s)
> are rather sensitive to the electronic and magnetic fields (H field would
> be my guess) emanating from cellular telephones.  One began alarming while
> I was making a call this afternoon (I was three or four feet away from the
> EPD).  I was able to confirm my suspicions by getting the second EPD to
[SNIP]

We have seen similar behavior adjacent to some microwave ovens and near
hand-held UHF radios, when transmitting.  The subject microwave ovens were
monitored for excessive microwave emissions with negative results.


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